Concrete made from Portland cement (also known as Ordinary Portland Cement (OPC)) is a material that can be used in civil engineering infrastructures. However, the production of Portland cement concrete typically results in large carbon dioxide emissions and consequently has a large carbon footprint. In an attempt to address these shortcomings, other materials such as, for example, geopolymers have been used as a substitute for Portland cement.
Geopolymer concrete provides an alternative low carbon footprint option to Portland cement concrete. Generally, geopolymer concrete is formed by mixing a binder (also known as cement) and aggregates (such as gravel and sand) with water. The binder typically includes metallurgical slags and/or coal fly ash mixed with an alkali liquid activator such as sodium hydroxide (also known as caustic soda). The alkali liquid activator serves to increase the reactivity of the solid components during the concrete preparation step.
A disadvantage of using alkali liquid activators is that they pose an Occupational Health and Safety (OH&S) hazard and may cause severe injuries such as chemical burns if spilt during transportation and/or concrete manufacture. These liquid activators may also pose an environmental hazard if they leak from their containment vessels and/or when they are discarded or disposed of.
Thus, there is a need for an activator for the production of geopolymer cement that makes it safe and easy to handle. Preferably, this geopolymer cement can produce concrete with comparable properties to concrete made with geopolymer cement made using a liquid alkali activator or with Portland cement.